// Press Shift twice to open the Search Everywhere dialog and type `show whitespaces`,
// then press Enter. You can now see whitespace characters in your code.
public class Main {
    public static void main(String[] args) {
      MobileTelephone m=new MobileTelephone();
      SIM s1=new SIMOfChinaMobile();
      m.useSIM(s1);
      m.print();


    SIM s2=new SIMOfChinaUnicom();
    m.useSIM(s2);
    m.print();
    }

}